Oncology: Mast Cell Tumour and Transitional Cell Tumours

Question 1

What is the most common diagnosed skin tumour in the dog?

Answer 1

Mast cell tumour

Other sites: subcut, conjunctiva, oral mucosa, GIT

Question 2

What is the clinical presentation of mast cell tumours?

Answer 2

• Cutaenous mass of variable appearance anywhere in the body
• Local effects- erytherma, oedeama, pruritus, haemorrhage
• Systemic- vomiting, melaena

Visceral form- metastasis

Question 3

How is mast cell tumour diagnosed?

Answer 3

FNA of the mass
* Usually diagnostic
* Characteristic purple granules

Question 4

How are mast cell staged?

Answer 4

Haematology/Biochem/Urinalysis
* Usually unremarkable
* Rule out co-morbs

FNA of biopsy of local LN
Abdominal US- assess liver, spleen, LNs
Thoracic radiographs- lung metastasis

Question 5

What affects prognosis of mast cells?

Answer 5

Clinical
* Location
* Breed
* Appearance
* Systemic illness
* Recurrence

Lab
* Histological grade

Question 6

What does each grade I- III mean?

Answer 6

Grade I
* Well differentiated tumours
* Benign behaviour
* Unlikely to cause death

Grade II
* Variably metastatic
* Can cause death
* Nodal metastasis- poor

Grade III
* Poorly differentiated
* Likely to be cause of death

Question 7

What margins are reccomended for mast cell tumour surgery?

Answer 7

3cm margins and 1 fascial plane
1-2cmfor grade I and II

I/II- potential to be curative

Incomplete margins:
* 1/4 grade II recur

Question 8

When could radiotherapy be given for mast cell tumours?

Answer 8

Post op or for local LN metastasis

Question 9

When is chemotherapy indicated for mast cell tumours?

What is commonly used?

Answer 9

• High grade or confirmed metastasis
• Neoadjunctively prior to surgery
• Residual microscopic disease

Vinblastine/prednisolone
or
Lomustine

TKIs- expensive

Question 10

1. How does feline cutaneous MCT commonly present?
2. Where is visceral most likely?

Answer 10

1. Cutaneous, raised, hairless massess- surgical excision usually curative
2. Splenic, intestinal

Question 11

1. Where are transitional cell carcinomas most commonly found?
2. Where do they commonly metastasise?

Answer 11

1. Bladder trigone but also urethra and prostate in males
2. Medial iliac LNs and other orfans

Question 12

What are presenting signs of TCC?

Answer 12

• Lower urinary tract signs- haematuria, stranguria, pollakyuria
• Occasionally signs related with bone metastasis
• ‘complicated UTI’

Question 13

How is TCC diagnosed?

Answer 13

Histopathological
Risk of seeding with FNA

Traumatic catheterisazation/prostatic wash
Cytoscopy

Question 14

How are TCC staged?

Answer 14

Haematology/biochemistry/urine analysis
* Neutrophilia, renal dysfunction, UTI

Abdominal US
Radiography- lung/bone metastasis

Question 15

How is TCC treated?

Answer 15

Surgery rarely possible
Medical treatment:
* NSAIDs- MST 181d
* Mitoxantrone and NSAIDs- MST 291d

Palliative care- regular urine cultures and ABs, cystostomy/urethral stents

Rapid deterioration